The group added in a letter: "We are asking you to initiate a regime of water testing which will test for and detect the drilling/cementing chemicals for as long as is required."

The campaigners also told how they believed the firm had failed to lay a sand layer meant to protect the area and warned that drivers from the company could have been exposed to potentially hazardous waste.

"The waste was taken (away) and containers were observed leaking liquid waste," they wrote. "We have to question whether the tanker drivers are aware of what they are carrying and the risks they are taking."